1) Field of the Invention
Embodiments of this invention relate to a window lock for securing frame members of a window to prevent relative adjustment of the frame members and, more particularly, to a window lock having a retention mechanism that automatically retains the lock in an unlocked configuration.
2) Description of Related Art
A typical sliding window includes two vertically adjustable frame members. When the window is closed and locked, the two frames are oriented vertically and a lock affixed to the top of the bottom frame member is engaged to a keeper affixed to the bottom of the top frame member. One conventional lock for such a sliding window includes a handle that is rotatable about a vertical axis. When the handle is rotated to its locked position, a hook-like arm rotates toward the top frame member and engages a corresponding hook-like arm defined by the keeper. The engagement of these two hook-like arms prevents the bottom frame from being raised or the top frame member from being lowered, thereby locking the window. In order to open the window, a person first rotates the handle of the lock to rotate the hook-like arm of the lock from the keeper. The lock then stays in the unlocked configuration until manually locked again.
A variety of automatic window locks have been proposed to automatically lock upon closing of the window and thereby eliminate the necessity for manually locking the window. One such conventional automatic window lock includes a retractable latch that can slide toward or away from the keeper. The latch is biased by a spring to its extended position so that, when the window is closed, the latch slides toward the keeper, and the keeper receives the latch to secure the window. A person can unlock the window by using a handle to retract the latch, overcoming the bias of the spring. Some automatic window locks require the user to manually hold the handle to keep the latch in the retracted position. Thus, in order to open the window, the person must manually hold the handle to overcome the force of the spring while also adjusting the position of one of the window frame members.
Alternatively, some automatically locking window locks are configured to remain unlocked until closed. For example, the lock can include a pivotably adjustable latch member that is configured to be biased toward the keeper until a button-like handle is actuated to rotate the latch member from the keeper. The handle stays in position once unlocked until the window is closed. Thus, the window can be opened without holding the handle in the unlocked position. Although the handle of such a lock can indicate whether the lock is locked or unlocked, a person unfamiliar with the particular lock must typically inspect the lock closely to determine the status of the lock, thereby increasing the difficulty of operating the lock.
Thus, there exists a need for an improved lock that can automatically lock upon closing of a window and that also can be automatically retained in an unlocked configuration, e.g., so that the window can be adjusted from a closed position to an open position without requiring the lock to be manually retained in the unlocked configuration. Further, the lock should facilitate easy operation, preferably even by a person that is unfamiliar with the particular operation of the lock.